Typewriting machines – Means auxiliary to typewriting function – Frame – casing – or support for typewriter
Reexamination Certificate
2002-06-21
2004-09-14
Hirshfeld, Andrew H. (Department: 2854)
Typewriting machines
Means auxiliary to typewriting function
Frame, casing, or support for typewriter
C400S589000, C400S605000, C400S613000
Reexamination Certificate
active
06789969
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a printer that prints to a continuous sheet medium, and relates more particularly to a printer having a mechanism for retracting a platen from a proximal position opposite a print head in conjunction with a cover opening operation. This invention also relates to a printer for printing to continuous sheet media and single-sheet media, and relates more particularly to a printer having a diversion unit for diverting continuous sheet and single sheet media.
2. Description of the Related Art
Printers having a storage unit for internally storing a paper roll as a type of continuous sheet print medium and pulling the roll paper (i.e. paper strip) off the paper roll in the storage unit for printing are known. Printers of this type have an opening part that is opened and closed by a cover. A paper roll is typically replaced and the inside of the printer is maintained through this opening part. When a paper roll is replaced, the paper must be pulled manually from the storage unit and set into the paper transportation path, and it is therefore preferable to locate the platen and transportation rollers forming one side of the paper transportation path on the side of the cover that opens and closes the opening to the storage unit. This configuration assures that the roll paper (i.e. paper strip) can be easily aligned in the paper transportation path when the cover is opened to change the paper roll because the platen and transportation rollers retract with the cover and thus open the paper transportation path.
Printers that use a common print head to print on both continuous sheet media and single sheet forms have also become common. Printers of this type can print on single sheet forms for issuing receipts, invoices, tickets, coupons, and other such forms, and are widely used in supermarkets and retail stores. Printers of this type preferably guide both continuous sheet media and single sheet media to a common printing position, and then eject the different types of media from different exit openings after being printed. A diversion unit for diverting continuous sheet media and single sheet media to different exit paths is therefore required at a position downstream from the print head.
The platen cannot be retracted with the cover in a printer that does not have a space in the platen retraction movement direction, and the diversion unit obstructs the platen retraction movement in printers that can print on both continuous sheet media and single sheet forms. The diversion unit can also interfere with opening and closing the cover. In addition to the diversion unit obstructing smooth opening and closing of the cover in this case, damage to the diversion unit or parts on the cover side could also result.
To address this problem JP-A-2000-118064 proposes retracting the platen in conjunction with the cover while avoiding interference with the paper exit diversion unit and other parts inside the printer by adding an operation for retracting the platen from an operative position (a position closely opposite the print head) in conjunction with a cover opening action and advancing the platen to the operative position in conjunction with a cover closing action. JP-A-2000-118064 achieves this action by using a large slide mechanism in order to retract the platen from the operative position opposite the print head, and thus presents problems such as described below.
(1) The sliding resistance of the slide mechanism could obstruct smooth opening and closing of the cover.
(2) Inclusion of a large slide mechanism tends to increase the printer size.
(3) Because the slide mechanism is retracted from above the paper roll storage unit, a wide space is needed around the printer in order to open the cover wide enough to retract the slide mechanism.
SUMMARY OF THE INVENTION
The present invention is directed to solving these problems and an object of the invention is to provide a printer which can retract the platen and transportation rollers while avoiding interference with internal printer parts when opening the cover, does not obstruct smooth opening and closing of the cover, invite an increase in printer size, or require a wide space around the printer, and can accurately position the movable platen to prevent print defects and form transportation problems.
A further object of the invention is to provide a printer having a diversion unit at a position downstream from the print head for diverting continuous sheet media and single sheet media. More particularly, this printer automatically retracts the diversion unit during a cover opening operation to a position where the diversion unit will not interfere with cover opening and closing, thereby enabling a smooth cover opening operation and preventing damage to the diversion unit. This printer can also improve the operability of the cover opening operation by releasing the cover lock and retracting the diversion unit as a result of linear operation of the cover release button.
To achieve this object a printer according to the present invention has a housing (including cover and unit frame) with a paper storage unit for holding a continuous sheet medium, a cover for opening and closing an opening to the paper storage unit, a print head for printing on the continuous sheet medium pulled out from the paper storage unit, a platen pivotally supported on the cover and movable between an inoperative and an operative position relative to the cover for guiding, in its operative position, a back surface of the continuous sheet medium at a position opposite the print head, and an abutment for engaging a fixed end side of the platen and rotating the free end side of the platen in conjunction with opening and closing the cover. It is therefore possible to retract the platen together with the cover without interfering with other internal parts of the printer when the cover is opened, and unlike a conventional sliding mechanism used to advance and retract the platen, the configuration of the present invention does not interfere with smooth opening and closing of the cover, invite an increase in printer size, or require a wide space around the printer.
Furthermore, a first movable transportation roller is preferably disposed at the free end side of the platen for transporting the continuous sheet medium between the first movable transportation roller and a first fixed transportation roller disposed on the frame side. In this case the continuous sheet medium can be easily aligned to the paper transportation path when the cover is closed.
Yet further preferably, a second movable transportation roller is disposed at the fixed end side of the platen for transporting the continuous sheet medium between the second movable transportation roller and a second fixed transportation roller disposed on the frame side. Continuous sheet medium transportation problems can thus be prevented by transporting the paper with a pair of first and second transportation rollers. In addition, by holding the continuous sheet medium with the first and second movable transportation rollers when the cover is closed, appropriate tension can be applied to the continuous sheet medium and printing defects caused by slack in the continuous sheet medium can be prevented.
Yet further preferably, the first movable transportation roller contacts the first fixed transportation roller on the upstream side of the print head after the second movable transportation roller contacts the second fixed transportation roller on the downstream side of the print head when the cover is operated to close. With this configuration the first and second movable transportation rollers apply pressure to the continuous sheet medium at different times, and as a result problems such as excessive force acting on the continuous sheet medium and the transportation rollers, and applying pressure to the continuous sheet medium while there is slack in the paper, can be avoided.
Further preferably, a positioning guide part is disposed on the free end side o
Hirabayashi Kenichi
Nagata Norio
Oshida Kazuya
Ghatt Dave A.
Haro Rosalio
Hirshfeld Andrew H.
Seiko Epson Corporation
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